Technical Field
The present invention relates to a cross-linked terpolymer, a method of making the terpolymer, and a method of removing lead ions from an aqueous solution wherein the terpolymer adsorbs the lead ions from the aqueous solution.
Description of the Related Art
The “background” description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description which may not otherwise qualify as prior art at the time of filing, are neither expressly or impliedly admitted as prior art against the present invention.
Sustainable water supplies are vital for human consumption, agriculture requirements and industry supplies. Wastewaters have always been a problem due to their increasing toxic threat to humans and the environment. Because of the development in technology and the increase in industrial activity, pollutants released into the environment have been increasing continuously. Due to their toxicity, there is a significant threat to the environment and public health (H. L. Ge, S. Liu, B. X. Su, L. T. g Qin, Predicting synergistic toxicity of heavy metals and ionic liquids on photobacterium Q67, J. Hazard. Mater., 268 (2014) 77-83; M. Oveka, T. Taká, Managing heavy metal toxicity stress in plants: Biological and biotechnological tools, Biotechnology Advances, 32, 1 (2014) 73-86—each incorporated herein by reference in its entirety).
Even at low levels, lead as heavy metal is toxic, non-biodegradable and tends to bio-accumulate in cells of living systems (M. Javed, M. A. Saeed, Growth and bioaccumulation of iron in the body organs of Catla catla, Labeo rohita and Cirrhina mrigala during chronic exposures, International Journal of Agriculture and Biology 12, 6 (2010) 881-886—incorporated herein by reference in its entirety). Lead poisoning in humans, especially in children six years old and under causes severe damage to organs like the kidney, nervous system, reproductive system, liver and brain (C. F. Bearer, Environmental health hazards: how children are different from adults, The future of children critical issues for children and youths, 5, 2 (1995) 11-26—incorporated herein by reference in its entirety). The primary sources of lead exposure for humans is lead-based paint in old-homes and lead in drinking water (H. W. Mielke and P. L. Reagan, Soil is an important pathway of human lead exposure, Environ health perspect. 106 (1998) 217-229; M. D. Sanborn, A. Abelsohn, M. Campbell, E. Weir, CMAJ 166, 10 (2002) 1287-1292—each incorporated herein by reference in its entirety).
As per the World Health Organization (WHO) standard, the maximum level of lead in drinking water is 0.01 mg/l, and as per the Drinking Water Standards and Health Advisories 2012 Edition, US Environmental Protection Agency, the maximum contaminant level goal of lead for drinking water is zero (WHO, Guidelines for Drinking-Water Quality, 3rd ed., World Health Organization, Geneva, Switzerland, 2006; Drinking Water Standards and Health Advisories, EPA 822-S-12-001, Office of Water U.S. Environmental Protection Agency Washington, D.C., 2012 Edition, U.S. Environmental Agency, Drinking Water Cont., http://www.epa.gov/safewater/contaminants/index.html—each incorporated herein by reference in its entirety). However, effluents discharged from various industries usually contain lead in an amount above this level. To achieve this goal, various technologies have been developed to remove lead from wastewaters. This includes precipitation, coagulation, reverse osmosis, ion exchange, solvent extraction, flotation, and membrane separation. However, among the various techniques, adsorption is considered the most efficient method for the treatment and elimination of lead in wastewater. This is because of its simple design and its merits of effectiveness, efficiency and free sludge (F. Rozada, M. Otero, A. Moran, A. I. Garcia. Adsorption of heavy metals onto sewage sludge-derived materials. Bioresource Technology 99 (2009) 6332-6338; Dabrowski, A. Adsorption, from theory to practice. Adv. Colloid Int. Sci. 93 (2001) 135-224; A. Celik, A. Demirbas, Removal of heavy metal ions from aqueous solutions via adsorption onto modified lignin from pulping wastes. Energy Sources 27 (2005) 1167-1177—each incorporated herein by reference in its entirety). Several materials have been investigated for the adsorption of lead (S. J. T. Pollard, G. D. Fowler, C. J. Sollars, and Perry, R. Low-cost adsorbents for waste and wastewater treatment: A review. Sci. Total Environ., 116 (1992) 31-37; S. E. Bailey, T. J. Olin, R. M. Bricka, and D. D. Adrian, A review of potentially low-cost sorbents for heavy metals. Water Res. 33 (1999) 2469-2473; S. Babel, and T. A. Kurniawan, Low-cost adsorbents for heavy metals uptake from contaminated water: A review. J. Hazard. Mater. 97 (2003) 219-225; S. S. Ahluwalia, and D. Goyal, Microbial and plant derived biomass for removal of heavy metals from wastewater. Bioresour. Technol. 98 (2007) 2243-2257; M. E. Russo, F. Di Natale, V. Prigione, V. Tigini, A. Marzocchella, G. C. Varese, Adsorption of acid dyes on fungal biomass: equilibrium and kinetics characterization. J. Chem. Eng. 162 (2010) 537-545; K. K. Singh, M. Talat, S. H. Hasan, Removal of lead from aqueous solutions by agricultural waste maize bran. Bioresour. Technol. 97 (2006) 2124-2130—each incorporated herein by reference in its entirety). Promising classes of polymeric adsorbents like cross-linked polymers that contain some carboxyl motifs (E. H. Rifi, F. Rastegar, J. P. Brunette, Uptake of cesium, strontium and europium by a poly(sodium acrylate-acrylic acid) hydrogel, Talanta 42 (1995) 811-816; C. Ozeroglu, G. Keceli, Removal of strontium ions by a crosslinked copolymer containing methacrylic acid functional groups, J. Radioanal. Nucl. Chem. 268 (2006) 211-219—each incorporated herein by reference in its entirety) like derivatives based on carboxylated polysaccharides (M. Wang, L. Xua, J. Peng, M. Zhai, Adsorption and desorption of Sr(II) ions in the gels based on polysaccharide derivates, J. Li, G. Wei, J. Hazard. Mater. 171 (2009) 820-826—incorporated herein by reference in its entirety) were also found to adsorb heavy metal ions. Chelating agents containing an aminomethylphosphonate moiety were tested and found to have attractive properties as exchange resins with ligands for selective metal ion complexation or phosphonic acid groups to extract heavy metal ions from aqueous solutions or from fuel ethanol solutions (K. P. Ripperger, S. D. Alexandratos, Polymer-supported phosphorus-containing ligands for selective metal ion complexation. In Studies in Surface Science and Catalysis; Dabrowski, A., Ed.; Elsevier Science B.V.: Amsterdam, The Netherlands, 120 (1998) 473-495; K. Yamabe, T. Ihara, A. Jyo, Metal ion selectivity of macroreticular chelating cation exchange resins with phophonic acid groups attached to phenyl groups of styrene-divinylbenzene copolymer matrix. Sep. Sci. Technol. 36 (2001) 3511-3528; D. Koodyńska, Z. Hubicki, M. Geüca, Application of a new generation complexing agent in removal of heavy metal ions from aqueous solutions. Ind. Eng. Chem. Res. 47 (2008) 3192-3199; Z. Wang, P. Yin, R. Qu, Q. Xu, Heterogeneous synthesis of chelating resin organophosphonic acid-functionalized silica gel and its adsorption property of heavy metal ions from fuel ethanol solutions. J. App. Polym. Sci. 126 (2012) 544-551—each incorporated herein by reference in its entirety). Diethylenetriamine-functionalized polymeric adsorbents, prepared by amination of micro-beads synthesized from glycidyl methacrylate and trimethylolpropane trimethacrylate co-polymerization, have been reported for selective removal of copper and lead ions (C. Liu, R. Bai, Q. S. Ly, Selective removal of copper and lead ions by diethylenetriamine-functionalized adsorbent: Behaviors and mechanisms, Water Res. 42 (2008) 1511-1522—incorporated herein by reference in its entirety). Amino/polycarboxylic acid functionalized polymeric adsorbents have been reported to have good chelating properties toward heavy metal ions and thus can be used for the treatment of waste water (E. Repo, J. K. Warchol, A. Bhatnagar, A. Mudhoo, M. Sillanpa, Aminopolycarboxylic acid functionalized adsorbents for heavy metals removal from water, Water Res. 47 (2013) 4812-4832; K. Inoue, K. Ohto, K. Yoshizuka, T. Yamaguchi, T. Tanaka, Adsorption of lead(II) ion on complexane types of chemically modified chitosan. Bull. Chem. Soc. Jpn. 70 (1997) 2443-2447; X. F. Liang, W. G. Hou, Y. M. Xu, G. H. Sun, L. Wang, Y. Sun, X. Qin, Sorption of lead ion by layered double hydroxide intercalated with diethylenetriaminepentaacetic acid. Colloid Surf. A 366 (2010) 50-57; L. Yang, Y. Li, X. Jin, Z. Ye, X. Ma, L. Wang, Y. Liu, Synthesis and characterization of a series of chelating resins containing amino/imino-carboxyl groups and their adsorption behavior for lead in aqueous phase. Chem. Eng. J. 168 (2011) 115-124; O. Karniz Junior, L. V. A. Gurgel, R. P. Freitas, L. F. Gil, Adsorption of Cu(II), Cd(II), and Pb(II) from aqueous single metal solutions by mercerized cellulose and mercerized sugarcane bagasse chemically modified with EDTA dianhydride (EDTAD). Carbohydr. Polym. 77 (2009) 643-650; L. Wang, L. Yang, Y. Li, Y. Zhang, X. Ma, Z. Ye, Study on adsorption mechanism of Pb(II) and Cu(II) in aqueous solution using PS-EDTA resin. Chem. Eng. J. 163 (2010) 364-372—each incorporated herein by reference in its entirety). Such materials have been also reported for their regenerability and recycling, which is a crucial step in increasing the practical applicability of the adsorbent (J. Huang, M. Ye, Y. Qu, L. Chu, R. Chen, Q. He, D. Xu, Pb(II) removal from aqueous media by EDTA—modified mesoporous silica SBA-15. J. Colloid Interface Sci. 385 (2012) 137-146—incorporated herein by reference in its entirety).